For the purpose of cutting body hair there are two customarily distinguished types of electrically powered appliances: the razor, and the hair trimmer or clipper. Where the razor is used for shaving, i.e. slicing body hairs at the level of the skin to as to obtain a smooth skin without stubbles, the hair trimmer is used to sever the hairs at a chosen distance from the skin, i.e. for cutting the hairs to a desired length. The difference in application is reflected by the different architectures of the cutting blade arrangement implemented on either appliance.
An electric razor typically includes a foil, i.e. an ultra thin perforated screen, and a cutter blade that is movable along the inside of the foil. During use, the outside of the foil is placed against the skin, such that any hairs that penetrate the foil are cut off by the cutter blade that moves against the inside thereof and fall into hollow hair collection portions inside the razor. An electric hair trimmer, on the other hand, typically includes two generally planar cutter blades with a toothed edge, one placed on top of the other such that the toothed edges overlap. In operation, the cutter blades reciprocate relative to each other, cutting off any hairs that are trapped between their teeth in a scissor action. The precise level above the skin at which the hairs are cut off is normally determined by means of an attachment, called a (spacer) guard or comb.